Mix-consistency indicator fob



Oct. 8, 1946.

c. I. BOHMER EIAL MIX-CONSISTENCY INDICATOR FOR CONCRETE MIXERS FiledMay 25, 1944 2 Sheets-Sheet l III/ll 1/ I Oct. 8, 1946.

c. l. BOHMER ET AL 2,409,014

NIX-CONSISTENCY INDICATOR FOR CONCRETE MIXERS Fiied lay 25, 1944 2Sheets-Sheet 2 Patented Oct. 8, 1946 MIX-CONSISTENCY INDICATOR FORCONCRETE MIXERS Clarence I. Bohmer and Arnold S. Millikin, Co-

lumbus, Ohio, assignors to The Jaeger Machine Company, Columbus, Ohio, acorporation of Ohio Application May 25, 1944, Serial No. 537,333

9 Claims. 1

This invention relates to an improved consistency or slump indicator fordetermining the degree of plasticity or the mixed condition of a body ofconcrete-forming materials contained in a rotary drum of a concretemixer during operation thereof.

In the active use of concrete mixers, it is important that the operatorshould be definitely and reliably informed when the mixing of thematerials has been carried out to the desired extent. While the priorart has proposed certain apparatus for accomplishing this generalpurpose, such prior apparatus has not, for various reasons, been usedcommercially to any considerable degree. In the main, it is believedthat prior proposals have been unduly complex in their structuraldesign, insufliciently rugged to withstand the rough usage to whichconcrete mixer appliances are subjected and also to the fact that theymay have been considered too costly to justify their practical use andadoption.

It is, therefore, a primary object of the invention to provide a strong,simple and reliable indicator formed to be carried by the revolving drumof a concrete mixer, and so constructed as to disclose externally of thedrum the consistency of the plastic mix after a given period ofagitation.

It is another object to provide a slump indicator for concrete mixerscomprising an open-sided housing provided in the outer peripheral wallof the mixer drum, the said housing being provided with bearings for thereception of a rotatable shaft, the ends of the shaft projecting intothe interior of the drum and being equipped with paddles adapted forengagement with the concreteforming mix as the latter is moved andagitated by the operation of the drum, yieldable means being provided toresist rotation of the shaft as turning forces are applied to the latterby the drum-contained mix, the shaft being provided with indicatingdevices, readable from the exterior of the drum, for disclosing thedegree of defiection of the shaft from its normal position, whereby themixer operator, by visually noting the operating positions of theindicating devices with reference to a graduated scale, may determinewith facility and accuracy the condition of the materials undergoingmixing.

For a further understanding of the invention, reference may be had tothe following description and the accompanying. drawings, wherein:

Fig. 1 is a side elevational view of a concrete mixer provided with aslump or consistency indicating means constituting the presentinvention;

Fig. 2 is a horizontal sectional view taken on the plane indicated bythe line II-II of Fig. 1;

Fig. 3 is a vertical sectional view on the plane indicated by the lineIII-III of Fig. 1;

Fig. 4 is an enlarged front elevational view of the indicating means;

Fig. 5 is a side elevational view, partly in section, of a concretemixer provided with a modified type of indicator;

Fig. 6 is a detail sectional view taken through the drum and itsbearings for the support of the indicator;

Fig. 7 is a fragmentary end elevational View of the drum of the mixerand the indicator.

Referring more particularly to the drawings, the numeral Iil designatesthe reversibly rotatable drum of a power driven concrete mixer. The

drum is suitably supported in connection with the base frame i I forrotation about its longitudinal axis and, in this connection, isprovided at one end with a ring !2 adapted for engagement with a cradlein the form of a plurality of frame-carried rollers 3. The opposite endof the drum may be equipped with the usual gear ring [4 by means ofwhich power may be applied to the drum to effect its rotation in thecustomary manner. The interior of the drum is equipped with the usualspiral blades [5 by means of which the mix, consisting of the mineralaggregate, cement and water, is agitated by being cascaded within thedrum and advanced generally from one end to the other thereof and thenreversed to move in the opposite direction. It will be understood thatthe mixer as thus far described is of standard design and operation and,therefore, a more extended explanation relative thereto is deemedunnecessary.

The present invention consists in the application to the drum of such amixer of an improved consistency or slump indicator by which the mixedstate of the concrete-forming materials within the drum may beexteriorly denoted while the mixer is in active operation. In thisregard, our improved indicating mechanism comprises an open-sidedhousing !6 which is mounted in. an opening I! formed in the peripheralwall of the drum ID. The body of the housing projects into the interiorof the drum at a position where. it does not interfere with the spiralagitating blades l5, and the outer portion of the housing is marginallyflanged as at l8 and welded or otherwise fastened to the outer surfacesof the drum wall, whereby to produce a rigid fluid-tight union betweenthe housing and the drum.

The housing is provided with longitudinally aligned bearing extensionsl9 which receive, in a preferred form of our invention, rubber bushingsof the Torflex type, each bushing consisting of inner and outerconcentrically arranged metallic bands 20 and 2|, respectively, whichare permanently joined to an interposed collar 22 of rubber or otherresilient pressure-deformable materials. The outer band 2| of eachbushing has a tight or press fit with the inner wall surfaces of thebearing extensions l3, while the inner bands 20 are correspondinglyfitted upon the outer surfaces of a paddle shaft 23. The fit andconstruction of the bushings is such as to normally restrain the shaft23 against rotation from its normal position. However, as rotatingforces are applied to the shaft, the rubber collars 22 of said bushingsadmit of limited rotation on the part of the shaft and againstprogressively increasing yielding resistance.

The ends of the shaft 23 project beyond the bushings into the interiorof the mixer drum and have bolted or otherwise fastened thereto, as at24, a pair of paddle members 25. These members are arranged in the pathsof mix movement within the interior of the drum, and as the mixincreases in consistency or plasticity, due to the agitation afforded bythe drum, the mix exerts greater and greater pressure on said paddlemembers, such pressures being used to cause rotation of the shaft 23against the resistance exerted thereon by the Torflex bearings. Thismovement of the shaft 23 is used to operate an externally viewableindicator mechanism.

Preferably, this mechanism consists of a plurality of arms indicated at26, 21 and 28. The outer arms 26 and 28 are provided with split hubs 29and 30, which have frictional clamping engagement with hearingextensions 3| projecting inwardly from the wall regions I 9. The outerends of the arms 26 and 28 are laterally bent as at 32 for movementrelative to a fixed graduated scale 34. The arm 21 has its hub secureddirectly to the shaft 23 for movement in unison with the paddle members25, the outer end of the arm 21 being disposed between the laterallybent outer ends of the arms 26 and 28.

In practice, the arms 26 and 28 are rotatable on the bearing extensions3| in unison with the movement of the indicator 21, the arms 26 and 28being so movable in accordance with the direction of rotation of themixing drum l0. Following maximum deflection of the indicator 21 and itssubsequent return to its normal or neutral position, under the influenceof the rubberized torsion bearings, the arm 26 or 28 which has beendeflected remains in its position of maximum defiection, so that whenthe rotation of the drum is stopped, the position of the deflected arm26 or 28 with reference to the scale graduations 34 may be duly noted bythe operator. Thereafter, the deflected arm is manually restored tocontact with the neutrally positioned indicator for a suc ceedingoperation. Thus, the arms 26 and 28 are moved in one directionautomatically by the indicator and are returned to a starting positionthrough a manually executed operation, there being enough frictionbetween the hubs of the arms 26 and 28 and the bearing extensions tohold said arms in their positions of maximum deflection.

It will be seen that as the shaft 23 rotates, the arm 21 will move inunison therewith and will engage one or the other of the arms 26 or 28,de-

sions 3|, these arms will remain in the positions to which they wereadvanced by the oscillation of the arm 21, thereby providing for anaccurate reading of the indicator irrespective of the oscillationsimparted to the shaft 23 during rotation of the drum in differentdirections.

Also, it will be seen that as the mix is cascaded within the drum of themixer and by the operation of the baffles l5 advanced toward one end ofthe drum and then toward its opposite end, the paddle members will bedeflected thereby, causing the shaft 23 to rotate against the resistanceoffered by the bushings indicated at 20, 2| and 22, thus causin theindicator arm to move over the scale 34 in one direction or the otherfrom a central position. By virtue of its external mounting, theindicator may be readily viewed by the mixer operator, and when theindicator arms reach a predetermined position with reference to saidscale, the operator wi11 thereby be apprised of the fact that the mixhas reached a condition suitable for pouring or discharge from themixer.

While the structure herein disclosed is preferred because of itsrelative simplicity, it is, of course, subject to certain variation ormodification without departing from its essential features. For example,the paddle shaft may be biased by a metallic sprin rather than byemploying the torsional bushings or a single indicator arm may be usedinstead of the plurality of arms here disclosed.

As shown in Figs. 5, 6 and 7, the shell of the drum la is provided atone end with a recess 35, in which is positioned stationary bearings 36for the reception of an indicator shaft 31. One end of this shaftprojects through an opening 38 into the interior of the drum, and islaterally bent as at 39 to receive a paddle member 48. The coil spring4| has one end thereof secured to the shaft 31 and its other end engagedwith a notch 42 provided in one of the bearings 36. The outer end of theshaft has fastened thereto the hub of an indicator arm 43 which ismovable over the graduated surface 44. As the consistency of the mixincreases, the latter exerts greater pressures on the paddle member 40,turning the shaft 31 against the resistance of the spring 4| and movingthe indicator 43 relative to the graduated surface 44. It will beobserved that in this form of our invention, as well as in the precedingform, the indicating mechanism is carried solely by the revolving drumand is viewable exteriorly of the latter to obtain desired readings,However, in the modified form, the indicating mechanism is disposed inone end of the mixer drum instead of at one side thereof. The paddlemember 40 is disposed so that regardless of the direction of rotation ofthe drum Ma, and the flow of the materials undergoing mixing in saiddrum, the indicator will function to disclose the consistency of themix, the spring 4| serving to maintain the indicator arm 43 in a givenor neutral position when relieved of the pressures of moving materialswithin the drum. However, during a mixing operation, the pressure impactof the moving batch of material on the paddle member will rock the shaft31 against an increasing yielding resist ance in actuating the indicatorarm.

We claim:

1. A consistency indicator for concrete mixers having a mix-receivingdrum, said indicator comprising an open-sided housing provided in thewall and extending into the interior of said drum, a shaft turnable inbearings provided in the walls of said housing, the ends of said shaftprojecting into said drum, mix-engaging paddle means disposed in andfixed to the ends of said shaft, said paddle means being arranged in thepaths of mix travel within said drum, yieldable means resisting turningmovement of said shaft from a normal position, and an indicator elementfixed to turn with said shaf, said indicater element being positioned insaid housin and having its outer end disposed for movement relative to agraduated surface provided on the exterior of said drum.

2. A slump indicator for concrete mixers having a mix-receiving drum,said indicator comprising a housing provided in the wall and extendinginto the interior of said drum, said housing having an open front,aligned torsion bushings fixed to the walls of said housing, a paddleshaft carried by said bearings to cause flexure of the latter whenrotated, mix-engaging paddle means received in said drum and fixed tosaid shaft, and an indicator element mounted to turn with said shaft,said indicator element being positioned in said housing and having itsouter end disposed for movement relative to a graduated surface viewablefrom the exterior of said drum.

3. A slump indicator for concrete mixers having a rotatablemix-receiving drum and agitating means disposed within said drum forcausing movement of the concrete mix contained therein longitudinally inboth directions of said drum, said indicator comprising a rotatableelement supported by the walls of said drum, paddle members connectedwith said rotatable element arranged in the paths of mix flow withinsaid drum, means yieldingly resisting rotation of said element in eitherdirection from a normal position, and an indicator element movable inunison with said rotatable element, said indicator element terminatingexteriorly of said drum for movement relative to a dual graduatedsurface provided on the exterior of said drum.

4:. In a concrete mixer of the type having a rotatable mix-receivingdrum and agitating and conveying blades provided internally of said drumfor causing the mix to travel longitudinally in both directions throughsaid drum while bein agitated, a slump indicator carried solely by saiddrum, said indicator embodying a rotatable element disposed both insideand outside of said drum, means yieldingly resisting rotation of saidelement in either direction from a normal position, mix-engaging paddlescarried by said element, said paddles being disposed in the paths ofmovement of the mix within said drum, and an externally viewableindicator mounted for rocking movement in unison with said element.

5. A slump indicator for concrete mixers having a rotatablemix-receiving drum, said indicator comprising an open-sided housingprovided in the outer wall of said drum, a rotatable element supportedby said housin a paddle member secured to said rotatable element anddisposed in the path of mix travel in said drum, resilient meansresisting rocking movement on the part of said element in response tomix pressures applied to said paddle member, and an indicator elementfixed to rock with said rotatable element, said indicator element beingpositioned in said housing and having its outer end disposed formovement relative to a graduated surface viewable from the exterior ofsaid drum.

6. A slump indicator for concrete mixers comprising an open-sidedhousing adapted to be secured to the outer Wall of a mixer drum, arockable element carried by said housing, resilient means resistingrocking movement of said ele-- ment in either direction from a normalposition, a paddle member secured to said element and disposed in thepaths of mix flow in the associated mixer drum, and an indicator elementmovable in unison with said element, said indicator element having itsouter end disposed for movement relative to a stationary graduatedsurface disposed exteriorly of the housing.

'7. Consistency indicating mechanism for concrete mixers comprising asupporting housing adapted to be mounted in a fixed position in theouter wall of a mixer drum, spaced aligned bearings provided in thewalls of said housing, a shaft extending through said bearings, bushingsdisposed in said bearings, each of said bushings embodying an outer bandfixed to its bearing and an inner band fixed upon said shaft and acollar of resilient material interposed between said bands and securedthereto, a paddle member fixed to said shaft and adapted to be disposedin the path of movement of a concrete mix agitated in the associateddrum, and an indicator arm fixed to said shaft for rotation in unisontherewith, the outer end of said arm being movable relative to agraduated surface provided exteriorly on said housing.

8. Mix consistency indicating mechanism for a concrete mixer of the typehaving a reversibly rotatable mix-receiving drum with agitatin meansdisposed within said drum, said mechanism comprising a rockable membersupported in bearings carried by said drum, yieldable means normallymaintaining said member in a fixed position of operation, paddle meanscarried by said member and arranged in the path of movement of the mixwithin said drum to effect rocking movement of said member against aprogressively increasing resistance offered by said yieldable means, andan indicator element mounted to oscillate in unison With said member,said element being Viewable exteriorly of said drum and movable toindicate mix consistency irrespective of the direction of rotation ofsaid drum.

9. Mix consistency indicating mechanism for a concrete mixer of the typehaving a reversibly rotatable mix-receiving drum with agitating meansdisposed within said drum, said mechanism comprising a rockable membersupported in bearings carried by said drum, yieldable means normallymaintaining said member in a fixed position of operation, paddle meanscarried by said member and arranged in the path of movement of the mixwithin said drum to effect rocking movement of said member against aprogressively increasing resistance offered by said yieldable means, anindicator element mounted to oscillate in unison with said member, saidelement being viewable exteriorly of said drum and movable to indicatemix consistency irrespective of the direction of rotation of said drum,and a pair of arms frictionally rotatable on said bearings, said armsbeing arranged on opposite sides of said indicator element in order tobe movable in unison with said element when the latter is deflected bythe actuation of said paddle means and to be restored manually intoengagement with said element when the latter occupies its normalundeflected position.

CLARENCE I. BOHMER. ARNOLD S. M'ILLIKIN.

